Circuit breaker



Dec. 24, 1929;

' J. N. TODD, JR

CIRCUIT BREAKER Filed June 16. 192

2 Sheets-Sheet 1 Dec. 24, 1929. TODD, JR 1,740,911

I CIRCUIT BREAKER Filed June 16. 1927 2 Sheets-Sheet 2 Patented Dec. 24,1929 UNITED. STATES PATENT oFFici:

JOHN NORTON TODD, JB., MONTGOMERY, ALABAMA, ASSIGNOR OE TWENTY PER CENTTO DAVID L. WHETSTONE AND TWENTY PER CENT TO WALTON M. BEASLEY,

BOTH OF MONTGOMERY, ALABAMA CIRCUIT BREAKER Application filed .Tune 16,

19 there is an over-load in the circuit. Another object of the inventionis to provlde a c1rcu1tbreaker which will open abruptly and positively.A further object is to supply a device of the class described which willbe compact in form, and so simple as to withstand hard use.

With the foregoing and other objects in view which will appear as thedescription proceeds, the invention resides in the combination andarrangement of parts and in the details of construction hereinafterdescribed and claimed, it being understood that changes in the preciseembodiment of the invention herein disclosed may be made within thescope of what is claimed, without departing from the spirit of theinvention.

In the drawings Figure 1 shows in side elevation, a device constructedin accordance with the invention;

Figure 2 is a top plan wherein the plug connection has been removed;

Figure 3 is a bottom plan;

Figure 4 is a section on the line 4-4 of Figure 1;

Figure Figure 2;

Figure 6 is a section on the line 6-6 of Figure 5;

Figure 7 is a Figure 5;

Figure 8 is a section on the hue 8-8 of Figure 5, the switch being open.Although the device may be disposed 1n any desired way with respect tothe hor zontal, it will be supposed that the article 1s arranged asshown in Figuresl, 5 and 6, of the drawings, the terms above, below, andthe like, being selected accordingly. In carrying out the invention,there is pro- 5 is a section on the line-55 of section on the line 77 ofvided a casing 1,: formed of insulating mate- 1927. Serial-No.199391.

vided with a hole 6 which shows in Figure V 3 of the drawings. A secondclosure 7 is seated in the upper end of the casing 1 on the lugs 4. Theclosure 7 has a curved slot 8 (Figure 2), and there are indicating marks9 on the closure 7, at the ends of the slot 8, the closure 7 beingprovided with a central opening 10.

A connecting finger 11 is mounted on the closure 7. An anchor plate 12is disposed below the partition 3. Securing elements 14 join the finger11 with the anchor plate'12 and extend through the closure 7, the lugs4, and the partition 3. An electrical connection, thus, is establishedbetween the connecting finger 11 and the anchor plate 12. A similarfinger 15 is mounted on the closure 7. An anchor plate 16 is locatedbeneath the partition 3. Securing elements 17 join the finger 15 withthe anchor plate 16, the securing elements 17 extending through theclosure 7, the lug 4, and the partition 3. The securing elements 17 jointhe connecting finger 15 electrically with the anchor plate 16.

An insulating disk 18 rests against the lower surface of the partition3. The disk 18 covers the anchor plate 16, as shown in Figure 7. Theinsulating disk 18, however, is cut away, as shown at 19 in Figure 7, toexpose part of the anchor ,plate 12.

An anchor strip 20 is placed on top of the partition 3. A base plate 21abuts against the lower surface of the insulating disk 18. Securingdevices 22, such as screws, connect the base plate 21 with the anchorstrip 20, and extend through the insulating disk 18 and the partition 3,as shown best in Figure 6. There are ears 23 on the base plate 21, andthe heads 24 and 25 of an electromagnet' 26 are secured as indicated at27, to the ears 23 on the base plate. One end 28 of the? winding of theelectromagnet 26 is in electrical engagement with a bolt 29 mounted inthe partition 3 and holding an upstanding spring switch member 30 on thepartition 3, as shown, for instance, in Figure 5. The other end 31 ofthe winding of the electromagnet 26 is bound between the anchor plate 12and the partition 3. A spring switchv member 32 is disposeddiametrically opposite to the switch member 30 and is held on thepartition 3 by a bolt 33, the said bolt'being engaged with the anchorplate 16.

The numeral 34 marks a shaft journaled in the anchor strip 20, in thepartition 3, in the insulating disk 18, and in the base plate 21. Theshaft 34 has a squared upper end 35 which is accessible through theopening 10 in the closure 7. An operating lever 36 is mountedintermediate its ends on the squared part 35 of the shaft 34, the lever36 being supplied with a finger piece 37 which moves in the curved slot8 of the closure 7.

The shaft 34 extends through a bridge 38 having, intermediate its ends,upstanding wings 39 in which there are seats 40 receiving is rotated.The bridge the ends of a cross pin 41 in the shaft 34, the constructionbeing such that bridge 38 is connected to the shaft 34 to swing when theshaft 38 has upstanding ends 42 which are adapted to cooperate with thespring switch members 32 and 30. An arm 43 is mounted on the squaredlower end 44 of the shaft 34, the arm 43 carrying a mark 45 which. whenthe arm is swung around far enough (Figure 3) is visible through thehole 6 in the first closure 5. The arm 43 has a reduced end 46 locatedin the same plane with the arm, the arm being provided at its free endwith an upstanding projection 47 located at right angles to the arm. Thelower portion of the shaft 34 is surrounded by a torsion spring 48, oneend of the spring being mounted in the arm 43, and the other end of thespring abutting, as shown in Figure 7 against a wing 49 that extendsdownwardly from the base plate 21.

The numeral 50 designates an armature pivotally mounted at 51 on thehead 25 of theelectromagnet 26. the armature being responsive to thehead 24 of the electromagnet, when the electromagnet is energized. Thearmature 50 is retracted by a draw spring, one end of the spring 52being connected to the armature 50, and the other end of the springbeing connected to the wing 49, as shown in Figure 7.

The plate 21 has a depending flange 53 in the side of which there is anotch 54. the flange 53 being provided with a lip 55 (Figure 6) which isdisposed parallel to the plate 21. A pivot element 56 is mounted inthelip 55 and in the base plate 21. An angular latch 57 is mounted to swingon the pivot element 56. One arm 58 of the latch 57 is loosely connectedby means of a screw 59 or the like, with the armature 50. The latch 57includes a hook-shaped keeper 60 wherewith the projection 47 on the arm43 is adapted to engage, the keeper 60 having a reduced finger 61 whichabuts against the flange 53, to limit the movement of the latch 57 underthe action of the armature 50, when the armature responds to the pull ofthe retractile spring 52.

The connecting fingers 11 and 15 are adapted to be received removably,in a well known way, in a plug connector 62 which is threaded forengagement with an electric lamp socket (not shown). The diameter of theplug connection 62 is such that it covers the slot 8 and the fingerpiece 37 on the operating lever 36. The utility of this feature will bemade manifest hereinafter.

The shaft 34 may be rotated by means of a key (not shown) applied to thesquared end 35 of the shaft, or the shaft may be rotated by means of thefinger piece 37 on the operating lever 36, the finger piece moving inthe slot 8 of the closure 7. When the shaft 34 is rotated as aforesaid,the ends 42 of the bridge 38 come into contact with the yieldable switchmembers 30 and 32. The torsion in the spring 48 is increased, and thearm 43 swings around until its projection 47 engages automatically withthe hook-shaped keeper 60 on the angular latch 57, the latch beingconnected to the armature 50, loosely, through the instrumentality ofthe screw 59, the spring 52 constituting both a retracting means for thearmature 50, and a means for holding the angular latch 57 in such aposition that the projection 47 on the arm 43 will automatically engagewith the keeper 60 of the latch 57 as aforesaid. When the projection 47on the arm 43 has been engaged with the keeper 60 on the latch 57, theshaft 34 is prevented from rotating reversely, responsive to the torsionspring 48, and the ends 42 of the bridge 38 are held engaged with theswitch members 30 and 32, as shown in Figure 5 of the drawings.

The circuit through the device comprises the finger -11, the securingelements 14, the anchor plate 12, the end 31 of the winding of theelectromagnet 26, the end 28 of the winding of the electromagnet, thebolt 29, the spring switch member 30, the bridge 38, the spring switchmember 32, the bolt 33, the anchor plate 16, the securing elements 17,and the finger 15, the fingers 11 and 15 being received in the plugconnection 62.

In case of an over-load, the head 24 of the electromagnet 26 attractsthe armature 50, the tension in the spring 52 being in creased, thescrew 59 transmitting motion from the armature 50 to the latch 57 by wayof the arm 58, the latch being tilted on its fulcrum 56, and the keeper60 on the latch rest in contact with the edge of the wing 49 shown inFigure 7. The indicating marks 9 of Figure 2 of course serve to advisethe operator as to Whether the circuit is opened operating lever 36 isinaccessible when the fingers 11 and 15 are engaged in the plugconnection. As a result, the device cannot be reset until the cause ofthe over-load has been corrected. If the cause of the over-load has notbeen corrected, the circuit will be opened as soon as the fingers 11 and15 are inserted again into the plug connection 62, and because thefinger piece 37 is concealed and coveredby the plug connection, theoperator cannot reach the finger piece 37 and hold the circuit closednotwithstanding the overload.

The device is simple in construction, compact, and is enclosed in acasing of insulating material. The cross piece 41 in the shaft 34 isreceived somewhat loosely in the seats 40 that are formed in the wings39 of the bridge 38. The result is that the shaft 34 is well inmotion,'before swinging movement is transmitted to the bridge '38, and,as a consequence, the bridge is moved abruptly and promptly to openposition with respect to the switch members 30 and 32, there being nosticking or dragging between the ends 42 of the bridge 38 and the switchmembers 30 and 32.

What is claimed is 1. In a device of the class described, a casing,over-load switch mechanism in the casing, means for closing theover-load switch mechanism at the will of an operator, said meanscomprising a part accessible from without the casing, a member forbringing the switch mechanism into a circuit, and a detachableconnection between said member and the switch mechanism, said memberbeing of such size as to render the aforesaid part of the closing meansinaccessible.-

2. In a device of the class described, a casing. having an opening,over-load switch to hold the shaft against rotation, means forsupporting the latch pivotally, means for rotating the shaft when thelatch is disengaged from the arm, a spring connected to the armature andconstituting both a retracting means for the armature and a means forholding the latch yieldingly in position to engage the arm, and switchmechanism carried by the shaft.

4. In a device of the class described, a casing provided intermediateits ends with a partition, a shaft journaled in the partition, springmeans for rotating the shaft, a bridge on the shaft. switch memberscooperating wit-h the bridge, the switch members and the bridge beinglocated on one side of the partition, and tripping means disposed on theopposite side of the partition, the tripping means comprising anelectromagnet in circuit with the switch members, an armature responsiveto the magnet, a latch operated by the armature, and an arm on the shaftand cooperating with the latch releasably to hold the shaft againstrotation.

In testimony that I claim the foregoing as my own, I have hereto aflixedmy signature.

'JOHN NORTON TODD, JR.

